1 00:00:05,160 --> 00:00:08,719 Speaker 1: From the brain's point of view, What is humor when 2 00:00:08,720 --> 00:00:12,719 Speaker 1: something is funny? Why do we breathe in and out rapidly? 3 00:00:13,320 --> 00:00:17,720 Speaker 1: Do other animals laugh? Why do most jokes come in threes? 4 00:00:18,440 --> 00:00:22,599 Speaker 1: What do mystery novelists, magicians and comedians have in common? 5 00:00:23,079 --> 00:00:30,200 Speaker 1: And could AI be truly funny? Welcome to Inner Cosmos 6 00:00:30,200 --> 00:00:33,280 Speaker 1: with me and David Eagleman. I'm a neuroscientist and author 7 00:00:33,320 --> 00:00:36,880 Speaker 1: at Stanford and in these episodes we sail deeply into 8 00:00:36,880 --> 00:00:40,760 Speaker 1: our three pound universe to understand why and how our 9 00:00:40,800 --> 00:00:45,320 Speaker 1: lives look the way they do. Today's episode is about humor. 10 00:00:52,920 --> 00:00:55,880 Speaker 1: Although humor is one of the most valued aspects of 11 00:00:55,920 --> 00:00:58,880 Speaker 1: our lives, you've probably heard very little about it from 12 00:00:58,960 --> 00:01:02,720 Speaker 1: the scientific point of view, and that changes today. So 13 00:01:02,840 --> 00:01:07,120 Speaker 1: why do we laugh? After all? It's very strange behavior. 14 00:01:07,680 --> 00:01:10,600 Speaker 1: Imagine that you are a space alien and you are 15 00:01:10,640 --> 00:01:14,800 Speaker 1: studying humans. So through years of study, you note that 16 00:01:14,920 --> 00:01:18,200 Speaker 1: humans seem to have a relatively high bandwidth channel of 17 00:01:18,280 --> 00:01:23,360 Speaker 1: communication by an extraordinarily rapid and precise use of their 18 00:01:23,920 --> 00:01:27,160 Speaker 1: larynx and their vocal cords. They move their tongue and 19 00:01:27,200 --> 00:01:29,840 Speaker 1: their lips very rapidly. They blow air at just the 20 00:01:29,920 --> 00:01:33,399 Speaker 1: right moments, and in this way they have language. They 21 00:01:33,440 --> 00:01:37,160 Speaker 1: communicate to each other at about thirty nine bits per second, 22 00:01:37,160 --> 00:01:40,400 Speaker 1: which is a pretty good transmission rate and way higher 23 00:01:40,440 --> 00:01:43,120 Speaker 1: than any other animal species as far as you the 24 00:01:43,200 --> 00:01:46,640 Speaker 1: alien can tell. But there's something else. These human creatures 25 00:01:46,680 --> 00:01:49,880 Speaker 1: do something that's very strange. Every once in a while, 26 00:01:50,440 --> 00:01:54,720 Speaker 1: they do a much lower frequency, lower bandwidth thing where 27 00:01:54,760 --> 00:02:00,240 Speaker 1: they make a series of rhythmic, involuntary contractions of their diaphragm, 28 00:02:00,640 --> 00:02:06,639 Speaker 1: which causes a sequence of vocalized exhalations, usually a series 29 00:02:06,720 --> 00:02:11,880 Speaker 1: of short repeated vowel sounds like ha or he or ho. Now, 30 00:02:12,040 --> 00:02:16,400 Speaker 1: you notice that this typically begins with some language or 31 00:02:16,440 --> 00:02:20,760 Speaker 1: event that triggers the brain's reward centers and lights up 32 00:02:20,760 --> 00:02:23,880 Speaker 1: something about the emotional networks, and that triggers the activation 33 00:02:24,040 --> 00:02:28,920 Speaker 1: of facial muscles, particularly around the mouth and eyes, And 34 00:02:29,040 --> 00:02:32,280 Speaker 1: often the human's mouth will open up wide and the 35 00:02:32,320 --> 00:02:35,240 Speaker 1: corners of the lips will get drawn back and upward, 36 00:02:35,840 --> 00:02:40,160 Speaker 1: and the respiratory starts doing these rapid cycles of inhalation 37 00:02:40,280 --> 00:02:44,840 Speaker 1: and exhalation, which throws a wrench in the normal breathing patterns, 38 00:02:45,360 --> 00:02:49,000 Speaker 1: and the heart rate increases and the blood pressure rises, 39 00:02:49,680 --> 00:02:53,120 Speaker 1: and the eyes might start to produce tears, and the 40 00:02:53,160 --> 00:02:56,600 Speaker 1: skin around the face might start turning red because of 41 00:02:56,639 --> 00:03:01,640 Speaker 1: the increased blood flow. Sometimes the whole body shakes or quivers, 42 00:03:01,720 --> 00:03:06,720 Speaker 1: especially in the shoulders and torso, and this physical manifestation 43 00:03:06,800 --> 00:03:10,760 Speaker 1: that can spread to the limbs, leading to movements like 44 00:03:11,120 --> 00:03:14,600 Speaker 1: clapping or slapping or bending over. Now, the question you 45 00:03:14,639 --> 00:03:18,360 Speaker 1: ask as the alien is why do they do this 46 00:03:18,520 --> 00:03:22,560 Speaker 1: strange laughing thing? Is there an evolutionary reason behind it? 47 00:03:22,720 --> 00:03:26,480 Speaker 1: Do any other animals on the planet do it? So 48 00:03:26,639 --> 00:03:30,840 Speaker 1: you go back to your alien university to present your findings, 49 00:03:31,200 --> 00:03:33,960 Speaker 1: and the faculty there drills you with questions that you're 50 00:03:33,960 --> 00:03:37,240 Speaker 1: supposed to know the answer to, like why do humans 51 00:03:37,400 --> 00:03:41,480 Speaker 1: go to clubs and movies with the hopes that they 52 00:03:41,520 --> 00:03:45,640 Speaker 1: will trigger a lot of these diaphragm contractions And if 53 00:03:45,720 --> 00:03:49,800 Speaker 1: they get fewer contractions than expected, do they seem disappointed? 54 00:03:50,480 --> 00:03:53,360 Speaker 1: Why do they get together with other humans that they 55 00:03:53,440 --> 00:03:56,600 Speaker 1: trust to stick food in their mouths and hope to 56 00:03:56,680 --> 00:04:00,720 Speaker 1: do these strange diaphragm contractions while eating, even though it's 57 00:04:00,840 --> 00:04:03,440 Speaker 1: dangerous and could cause them to choke on their food. 58 00:04:03,680 --> 00:04:06,400 Speaker 1: So we're going to take this in a few acts. First, 59 00:04:06,400 --> 00:04:08,960 Speaker 1: we're going to address what is humor, And in the 60 00:04:09,000 --> 00:04:12,760 Speaker 1: second act we'll ask why do we laugh? In other words, 61 00:04:12,760 --> 00:04:14,960 Speaker 1: why do we do it out loud instead of silently. 62 00:04:15,160 --> 00:04:18,600 Speaker 1: So let's start with the general notion of comedy about 63 00:04:18,640 --> 00:04:21,880 Speaker 1: something being funny. As it turns out, people have been 64 00:04:21,960 --> 00:04:25,159 Speaker 1: wondering about this for a long time, and the first 65 00:04:25,200 --> 00:04:30,000 Speaker 1: known theories about humor go back to Plato. Now, Plato 66 00:04:30,440 --> 00:04:34,120 Speaker 1: had a very dim view of laughter. He generally saw 67 00:04:34,160 --> 00:04:37,880 Speaker 1: it as something malicious that people do. In his view, 68 00:04:38,080 --> 00:04:42,760 Speaker 1: audiences laugh at people who have ignorance about themselves, who 69 00:04:42,800 --> 00:04:46,200 Speaker 1: imagine themselves to be richer than they are, or better 70 00:04:46,240 --> 00:04:48,719 Speaker 1: looking than they are, or more virtuous than they are, 71 00:04:49,360 --> 00:04:51,880 Speaker 1: and we laugh at them, which he found to be 72 00:04:52,000 --> 00:04:56,719 Speaker 1: a morally objectionable thing to do. Now, his student Aristotle 73 00:04:56,880 --> 00:05:00,800 Speaker 1: appreciated wit in conversation, but he agreed with Plato that 74 00:05:01,000 --> 00:05:05,000 Speaker 1: people laugh at the misfortunes or mistakes of others, which 75 00:05:05,400 --> 00:05:10,320 Speaker 1: reinforces their own sense of self worth and status. Think 76 00:05:10,400 --> 00:05:13,400 Speaker 1: of an audience laughing at a character in a comedy 77 00:05:13,760 --> 00:05:17,279 Speaker 1: who's consistently making foolish mistakes. So this is what's known 78 00:05:17,320 --> 00:05:22,320 Speaker 1: nowadays as superiority theory, and the idea is that comedy 79 00:05:22,360 --> 00:05:26,480 Speaker 1: stems from feelings of being better than other people, and 80 00:05:26,520 --> 00:05:29,520 Speaker 1: no one really challenged this idea that that's what comedy 81 00:05:29,560 --> 00:05:34,040 Speaker 1: was about. Until the mid eighteenth century people started to think, 82 00:05:34,600 --> 00:05:37,719 Speaker 1: wait a minute, you don't really need feelings of superiority 83 00:05:37,760 --> 00:05:41,359 Speaker 1: to laugh at something. Just think of a funny poem 84 00:05:41,440 --> 00:05:46,160 Speaker 1: or pun. And on the flip side, we often feel superior, 85 00:05:46,240 --> 00:05:48,240 Speaker 1: like the way you might feel superior to a horse 86 00:05:48,320 --> 00:05:51,560 Speaker 1: or a squirrel, but that doesn't mean we laugh at them. 87 00:05:51,760 --> 00:05:55,200 Speaker 1: So other theories began to blossom, and now there are 88 00:05:55,640 --> 00:05:59,360 Speaker 1: many theories of humor. One of them, for example, is 89 00:05:59,560 --> 00:06:04,000 Speaker 1: relae theory. This was originally proposed by A Lord Shaftsbury 90 00:06:04,040 --> 00:06:08,279 Speaker 1: in the seventeen fifties, and he suggested the slightly strange 91 00:06:08,320 --> 00:06:12,520 Speaker 1: idea that we laugh to release animal spirits that have 92 00:06:12,600 --> 00:06:15,599 Speaker 1: built up inside us. Now, this doesn't make much sense 93 00:06:15,640 --> 00:06:19,320 Speaker 1: in our modern vocabulary, but later proponents of this idea, 94 00:06:19,480 --> 00:06:23,400 Speaker 1: like Sigmund Freud and Herbert Spencer, they cast this same 95 00:06:23,480 --> 00:06:27,159 Speaker 1: idea in a different light. They said, look, humor is 96 00:06:27,200 --> 00:06:32,919 Speaker 1: a way to release psychological tension or suppressed emotions, like 97 00:06:33,000 --> 00:06:35,599 Speaker 1: think of laughing at a joke that touches on a 98 00:06:35,600 --> 00:06:40,200 Speaker 1: taboo subject. So laughter serves as a release valve for 99 00:06:40,400 --> 00:06:43,960 Speaker 1: pent up energy in your nervous system, and in this view, 100 00:06:44,000 --> 00:06:47,279 Speaker 1: it's a purely physiological issue. And you see this happen 101 00:06:47,360 --> 00:06:51,720 Speaker 1: sometimes when someone laughs at a totally inappropriate moment, like 102 00:06:52,040 --> 00:06:55,440 Speaker 1: someone has died, and the excess energy comes out in 103 00:06:55,440 --> 00:07:00,599 Speaker 1: a way that looks different from what they're feeling internally. Relatedly, 104 00:07:00,680 --> 00:07:04,440 Speaker 1: by the way, Freud also suggested that humor and laughter 105 00:07:04,560 --> 00:07:07,880 Speaker 1: might act as a defense mechanism, and in this way 106 00:07:07,920 --> 00:07:12,920 Speaker 1: it allows people to deal with uncomfortable emotions or social tensions, 107 00:07:13,320 --> 00:07:15,800 Speaker 1: and it can reduce stress and anxiety. But there are 108 00:07:15,800 --> 00:07:18,920 Speaker 1: other ways that people look at humor. One very common 109 00:07:18,920 --> 00:07:21,920 Speaker 1: school of thought looks at humor as a way of 110 00:07:22,080 --> 00:07:27,240 Speaker 1: indicating play. It says, look, play is absolutely essential for 111 00:07:27,520 --> 00:07:29,920 Speaker 1: learning how to do real things in the world. And 112 00:07:29,960 --> 00:07:34,800 Speaker 1: so the idea is that humor engages all this cognitive 113 00:07:34,840 --> 00:07:40,160 Speaker 1: practice and social practice in a playful context. For example, 114 00:07:40,160 --> 00:07:44,000 Speaker 1: look at the way that children engage in silly wordplay 115 00:07:44,400 --> 00:07:49,960 Speaker 1: or crazy imaginative scenarios. That stuff cracks them up. They're playing. 116 00:07:50,760 --> 00:07:52,920 Speaker 1: And there's a closely related way of looking at this too. 117 00:07:53,040 --> 00:07:57,120 Speaker 1: When that evolutionary psychologists like the idea that humor and 118 00:07:57,200 --> 00:08:01,440 Speaker 1: laughter is all about social bonding. Humor is a tool 119 00:08:01,640 --> 00:08:06,240 Speaker 1: for strengthening the bonds within a group. You build cohesion 120 00:08:06,280 --> 00:08:09,280 Speaker 1: this way, you build a sense of community. So just 121 00:08:09,280 --> 00:08:12,520 Speaker 1: think about inside jokes that you do with your friends 122 00:08:13,200 --> 00:08:17,960 Speaker 1: that reinforce your group identity and your camaraderie. And I 123 00:08:18,000 --> 00:08:21,960 Speaker 1: think that the slang that each generation introduces is a 124 00:08:22,000 --> 00:08:24,880 Speaker 1: form of the same thing, making sure that the adults 125 00:08:24,880 --> 00:08:27,320 Speaker 1: are on the outside and you and your pals are 126 00:08:27,320 --> 00:08:31,080 Speaker 1: on the inside. It's a way of bonding. Now, the 127 00:08:31,200 --> 00:08:35,400 Speaker 1: ideas about humor don't end there. Other thinkers like Marvin 128 00:08:35,440 --> 00:08:40,280 Speaker 1: Minsky and Jerry Saul's focus on a different aspect of humor, 129 00:08:40,320 --> 00:08:45,640 Speaker 1: the cognitive aspect. They care about the mental processes involved 130 00:08:45,640 --> 00:08:49,160 Speaker 1: in understanding and appreciating comedy. So they're looking at the 131 00:08:49,679 --> 00:08:54,120 Speaker 1: cognitive effort required to understand some cognitive play on words. 132 00:08:54,280 --> 00:08:57,280 Speaker 1: So take a joke like this today. I found a 133 00:08:57,320 --> 00:09:01,560 Speaker 1: book with the title how to Solve fifty of Life's Problems, 134 00:09:01,960 --> 00:09:04,520 Speaker 1: So I bought two of them. So the last sentence 135 00:09:04,559 --> 00:09:07,680 Speaker 1: comes as a surprise, and the brain goes back and 136 00:09:07,720 --> 00:09:11,720 Speaker 1: tries to reinterpret what it heard. There's a puzzle in there. 137 00:09:12,240 --> 00:09:17,640 Speaker 1: Which forces you to reshape your interpretation, or specifically, your 138 00:09:17,760 --> 00:09:22,400 Speaker 1: interpretation of the speaker's interpretation. And then it falls into 139 00:09:22,400 --> 00:09:24,840 Speaker 1: place that there's another way to see this, and it 140 00:09:24,960 --> 00:09:29,520 Speaker 1: strikes us as funny because it's both nonsensical and a 141 00:09:29,559 --> 00:09:33,360 Speaker 1: little bit sensical. And some other theories zoom in even 142 00:09:33,440 --> 00:09:35,440 Speaker 1: more on the types of humor that have to do 143 00:09:35,520 --> 00:09:39,040 Speaker 1: with linguistics, in other words, about the structure and use 144 00:09:39,080 --> 00:09:43,480 Speaker 1: of language, like wordplay or jokes that rely on double 145 00:09:43,600 --> 00:09:48,040 Speaker 1: meanings like I'm addicted to break fluid, but it's okay 146 00:09:48,120 --> 00:09:52,080 Speaker 1: because I can stop at any time, or jokes that 147 00:09:52,160 --> 00:09:56,120 Speaker 1: rely on homophones, like a photon checks into a hotel, 148 00:09:56,480 --> 00:09:59,080 Speaker 1: the front desk asks if it has any luggage and 149 00:09:59,120 --> 00:10:03,000 Speaker 1: it says, no, Oh, I'm traveling light. So the punchline 150 00:10:03,040 --> 00:10:05,800 Speaker 1: is a phrase that can be reinterpreted and has two 151 00:10:05,880 --> 00:10:11,200 Speaker 1: meanings that surprisingly fit. Now, fundamentally, your brain is always 152 00:10:11,200 --> 00:10:13,800 Speaker 1: trying to squeeze the complexity of the world down to 153 00:10:13,880 --> 00:10:17,720 Speaker 1: a single interpretation. And something about the back and forth 154 00:10:17,760 --> 00:10:22,520 Speaker 1: here between two interpretations that can both work makes something funny. 155 00:10:22,920 --> 00:10:26,640 Speaker 1: Or take a kid's joke like why aren't lobsters generous 156 00:10:27,000 --> 00:10:31,400 Speaker 1: because they're shellfish? This relies on two sounds that are 157 00:10:31,440 --> 00:10:34,400 Speaker 1: almost the same, so your brain entertains them both and 158 00:10:34,480 --> 00:10:38,960 Speaker 1: finds humor in the surprise that they both work. So 159 00:10:39,440 --> 00:10:41,920 Speaker 1: I've told you about two thousand years of people making 160 00:10:42,000 --> 00:10:46,160 Speaker 1: theories about humor. It's about superiority, it's about releasing tension, 161 00:10:46,320 --> 00:10:50,120 Speaker 1: it's about play, it's about social bonding or linguistics or 162 00:10:50,120 --> 00:10:53,040 Speaker 1: so on. And the thing to appreciate here is that 163 00:10:53,080 --> 00:10:57,280 Speaker 1: these aren't mutually exclusive. Each of these theories has something 164 00:10:57,320 --> 00:11:01,880 Speaker 1: to say about some element of humor, provide a different lens. 165 00:11:02,520 --> 00:11:06,480 Speaker 1: And what this proliferation of theories really highlights is the 166 00:11:06,600 --> 00:11:11,000 Speaker 1: multifaceted nature of humor and all the processes cognitive and 167 00:11:11,120 --> 00:11:17,000 Speaker 1: emotional and social involved in finding something funny. So if 168 00:11:17,040 --> 00:11:19,160 Speaker 1: you are that space alien, you'd find there's not just 169 00:11:19,240 --> 00:11:22,360 Speaker 1: one single answer for your colleagues who are peppering you 170 00:11:22,400 --> 00:11:26,600 Speaker 1: with questions and trying to understand earth humor. Instead, you'd 171 00:11:26,600 --> 00:11:28,559 Speaker 1: have to come to the conclusion that there are many 172 00:11:28,679 --> 00:11:32,839 Speaker 1: angles to this strange behavior. But we haven't even gotten 173 00:11:32,880 --> 00:11:34,680 Speaker 1: to the best angle yet. I want to zoom in 174 00:11:34,720 --> 00:11:37,680 Speaker 1: on one theory in particular that I think sits right 175 00:11:37,800 --> 00:11:41,320 Speaker 1: at the center of much of comedy, and that has 176 00:11:41,360 --> 00:11:46,800 Speaker 1: to do with the violation of expectation. The engine of 177 00:11:46,960 --> 00:11:52,360 Speaker 1: most jokes involves setting up an expectation and then breaking it. Now, 178 00:11:52,360 --> 00:11:55,200 Speaker 1: why does that work. It's because the brain is constantly 179 00:11:55,600 --> 00:12:00,480 Speaker 1: predicting what it thinks is likely to happen, and in 180 00:12:00,520 --> 00:12:05,000 Speaker 1: certain circumstances, when the next steps seem clear, but then 181 00:12:05,000 --> 00:12:09,360 Speaker 1: they're suddenly violated, that's often funny. So this theory of 182 00:12:09,440 --> 00:12:13,480 Speaker 1: humor is called incongruity theory, and the school of thought 183 00:12:13,559 --> 00:12:17,440 Speaker 1: is favored by philosophers like Emmanuel Kant and Arthur Schopenhauer, 184 00:12:17,920 --> 00:12:21,920 Speaker 1: and it suggests that humor arises when there's a discrepancy 185 00:12:22,000 --> 00:12:24,520 Speaker 1: between what you think is about to happen and what 186 00:12:24,640 --> 00:12:28,520 Speaker 1: actually happens. So let's take an example. I saw a 187 00:12:28,559 --> 00:12:32,440 Speaker 1: post on social media yesterday that read, my husband and 188 00:12:32,480 --> 00:12:35,160 Speaker 1: I have reached the difficult decision that we do not 189 00:12:35,280 --> 00:12:39,280 Speaker 1: want children. If anybody does, send me your contact details 190 00:12:39,280 --> 00:12:42,360 Speaker 1: and we can drop them off tomorrow. So your brain 191 00:12:42,520 --> 00:12:46,400 Speaker 1: starts off with a particular understanding and then that's tripped up. 192 00:12:47,080 --> 00:12:50,640 Speaker 1: Or here's another example. My dog used to chase people 193 00:12:50,640 --> 00:12:53,040 Speaker 1: on bikes a lot. It got so bad that I 194 00:12:53,120 --> 00:12:55,640 Speaker 1: finally had to take his bike away. Now, jokes like 195 00:12:55,679 --> 00:12:59,640 Speaker 1: this work in part because language is so low bandwidth. 196 00:12:59,760 --> 00:13:03,040 Speaker 1: When you hear the sentence, you're making lots of assumptions 197 00:13:03,240 --> 00:13:08,360 Speaker 1: unconsciously under the hood without ever realizing it. Another example 198 00:13:08,600 --> 00:13:11,800 Speaker 1: is the way that we predict words ahead of hearing 199 00:13:11,840 --> 00:13:15,560 Speaker 1: them again without even realizing it. So any comedy can 200 00:13:15,600 --> 00:13:18,560 Speaker 1: take advantage of that. So I can tell you last 201 00:13:18,679 --> 00:13:22,559 Speaker 1: month I got diagnosed as being colorblind. That really came 202 00:13:22,600 --> 00:13:25,520 Speaker 1: out of the orange. Now there's only a surprise there 203 00:13:25,920 --> 00:13:29,600 Speaker 1: because your brain was predicting what it thought was going 204 00:13:29,679 --> 00:13:32,720 Speaker 1: to come next. And this is the reason so many 205 00:13:32,840 --> 00:13:36,960 Speaker 1: jokes are structured in patterns of threes. The first guy 206 00:13:37,160 --> 00:13:41,320 Speaker 1: does something, and then the second guy establishes the pattern. 207 00:13:41,840 --> 00:13:44,160 Speaker 1: Then your brain has a clear prediction for what the 208 00:13:44,200 --> 00:13:47,000 Speaker 1: third guy is going to do, and the comedy comes 209 00:13:47,040 --> 00:13:50,880 Speaker 1: when he breaks that pattern. So a structure of three 210 00:13:51,520 --> 00:13:56,360 Speaker 1: is the fastest possible path to setting an expectation and 211 00:13:56,400 --> 00:13:58,800 Speaker 1: then swerving off that road. And by the way, this 212 00:13:59,000 --> 00:14:02,800 Speaker 1: issue about the brain setting expectations, this is something that 213 00:14:02,840 --> 00:14:05,240 Speaker 1: you can start seeing in the first few months of life, 214 00:14:05,720 --> 00:14:08,960 Speaker 1: even well before infants have language. You can study this, 215 00:14:09,040 --> 00:14:12,560 Speaker 1: and that's because when an infant is surprised by something, 216 00:14:12,559 --> 00:14:15,360 Speaker 1: they'll pay more attention to it. So, for example, you 217 00:14:15,400 --> 00:14:18,440 Speaker 1: put a teddy bear behind a screen, and then you 218 00:14:18,520 --> 00:14:21,640 Speaker 1: remove the screen and now there's a rabbit there. Even 219 00:14:21,680 --> 00:14:24,440 Speaker 1: a very young infant will stare and stare at that, 220 00:14:24,680 --> 00:14:27,920 Speaker 1: indicating that even though they can't speak to you yet, 221 00:14:28,240 --> 00:14:32,040 Speaker 1: their brain had set up in expectation and the rabbit 222 00:14:32,200 --> 00:14:51,400 Speaker 1: doesn't match it. One way that we know that comedy 223 00:14:51,480 --> 00:14:55,920 Speaker 1: is about breaking expectations is because comedy has to surprise. 224 00:14:56,640 --> 00:14:59,240 Speaker 1: Imagine that you're at a dinner party and the guy 225 00:14:59,280 --> 00:15:02,000 Speaker 1: across from you tells a good joke and everybody laughs, 226 00:15:02,400 --> 00:15:05,760 Speaker 1: and then he tells exactly the same joke a second time. 227 00:15:06,040 --> 00:15:09,080 Speaker 1: It would be zero funny. The second time everyone would 228 00:15:09,240 --> 00:15:11,880 Speaker 1: look at one another. So what does that tell us? 229 00:15:12,280 --> 00:15:16,600 Speaker 1: That something funny has to surprise. So what we've seen 230 00:15:16,720 --> 00:15:20,880 Speaker 1: so far is that humor has to betray your expectations. 231 00:15:20,920 --> 00:15:24,160 Speaker 1: But I've left something out so far. There's another element 232 00:15:24,440 --> 00:15:28,360 Speaker 1: to something being funny, because we quite often find that 233 00:15:28,440 --> 00:15:31,760 Speaker 1: our expectations don't get fulfilled, and almost all of these 234 00:15:31,800 --> 00:15:36,960 Speaker 1: situations aren't actually funny. Imagine you open your suitcase and 235 00:15:36,960 --> 00:15:40,440 Speaker 1: you realize that you grabbed the wrong one at the airport. 236 00:15:40,840 --> 00:15:44,120 Speaker 1: That would be surprising, Or an airplane engine suddenly falls 237 00:15:44,160 --> 00:15:47,080 Speaker 1: onto the roof of your car. That would certainly violate 238 00:15:47,120 --> 00:15:51,200 Speaker 1: your expectations, but it wouldn't be funny at all. So 239 00:15:51,320 --> 00:15:56,200 Speaker 1: comedy requires a second element. It requires a sense of harmlessness. 240 00:15:56,920 --> 00:16:01,440 Speaker 1: If some event or some punchline triggers fear or anxiety 241 00:16:01,560 --> 00:16:05,240 Speaker 1: or disgust or whatever instead of amusement, it's not funny. 242 00:16:05,720 --> 00:16:11,520 Speaker 1: Humor requires a very delicate balance of unexpected and harmless. 243 00:16:11,920 --> 00:16:14,040 Speaker 1: And by the way, I should specify that this means 244 00:16:14,080 --> 00:16:18,280 Speaker 1: a sense of harmlessness for the listener. There can be 245 00:16:18,760 --> 00:16:22,480 Speaker 1: cruel jokes against other groups of people, out groups, and 246 00:16:22,520 --> 00:16:25,400 Speaker 1: the jokes can involve bad things happening to them, But 247 00:16:25,480 --> 00:16:29,360 Speaker 1: the idea is that the listener doesn't feel threatened. So 248 00:16:30,080 --> 00:16:32,120 Speaker 1: if you are the space alien and you are being 249 00:16:32,240 --> 00:16:35,720 Speaker 1: quizzed about what is required for human comedy, that's the 250 00:16:35,760 --> 00:16:38,480 Speaker 1: main thing. It has to surprise and it has to 251 00:16:38,560 --> 00:16:41,080 Speaker 1: not threaten the listener. And we'll come back to this 252 00:16:41,120 --> 00:16:43,560 Speaker 1: in a few minutes, but first I want to mention 253 00:16:43,680 --> 00:16:45,800 Speaker 1: that I was thinking about this harmlessness issue the other 254 00:16:45,880 --> 00:16:48,360 Speaker 1: day and I realized this is consistent with something that 255 00:16:48,440 --> 00:16:52,120 Speaker 1: I read from Woody Allen many years ago. He said, 256 00:16:52,680 --> 00:16:59,120 Speaker 1: comedy equals tragedy plus time. In other words, events that 257 00:16:59,200 --> 00:17:03,520 Speaker 1: are pain full or upsetting can over time become sources 258 00:17:03,560 --> 00:17:08,760 Speaker 1: of humor. The time gives some emotional distance, so when 259 00:17:08,800 --> 00:17:13,560 Speaker 1: something tragic first occurs, the emotions around it, like the 260 00:17:13,720 --> 00:17:16,400 Speaker 1: grief and the anger and the shock, they're too raw 261 00:17:16,560 --> 00:17:19,679 Speaker 1: for people to find anything funny about the situation. But 262 00:17:19,760 --> 00:17:24,440 Speaker 1: as time passes, emotions tend to soften, the pain goes down, 263 00:17:24,840 --> 00:17:27,200 Speaker 1: and people can look back on an event with a 264 00:17:27,240 --> 00:17:31,840 Speaker 1: different mindset, and sometimes they see absurdities or ironies that 265 00:17:31,880 --> 00:17:35,440 Speaker 1: weren't apparent before. So you and your partner lose your 266 00:17:35,440 --> 00:17:38,679 Speaker 1: tempers about something because you said X and your partner 267 00:17:38,680 --> 00:17:42,160 Speaker 1: thought you meant why, and you're both furious. But six 268 00:17:42,200 --> 00:17:44,960 Speaker 1: months later you both love telling the story and you 269 00:17:45,000 --> 00:17:47,920 Speaker 1: get comic value from it each time. And, by the way, 270 00:17:47,960 --> 00:17:51,200 Speaker 1: comedians use this all the time to craft new material. 271 00:17:51,240 --> 00:17:53,800 Speaker 1: The idea is that with just the right amount of time, 272 00:17:54,440 --> 00:17:57,960 Speaker 1: this sting of some tragic event can fade enough that 273 00:17:58,040 --> 00:18:02,040 Speaker 1: people can laugh at it without guilty or uncomfortable. But 274 00:18:02,080 --> 00:18:05,359 Speaker 1: the time component is crucial because the comedian has to 275 00:18:05,400 --> 00:18:09,119 Speaker 1: be sure that the audience is ready to find humor 276 00:18:09,160 --> 00:18:12,160 Speaker 1: in the tragedy. In any case, time works because sometimes 277 00:18:12,160 --> 00:18:16,480 Speaker 1: we have a perspective shift, we've changed how we collectively 278 00:18:16,560 --> 00:18:20,119 Speaker 1: interpret the event, and sometimes it's just a coping mechanism. 279 00:18:20,440 --> 00:18:22,520 Speaker 1: But in any case, this comes back to the point 280 00:18:22,760 --> 00:18:26,639 Speaker 1: that humor can't be something that is directly threatening to 281 00:18:26,720 --> 00:18:30,000 Speaker 1: us right now, So let's return to incongruity theory, which 282 00:18:30,000 --> 00:18:34,160 Speaker 1: is that something funny has to violate your expectations. Now 283 00:18:34,280 --> 00:18:37,560 Speaker 1: that's how this is thought about by philosophers. But now 284 00:18:37,560 --> 00:18:39,639 Speaker 1: that neuroscience is on the scene, I think there's an 285 00:18:39,680 --> 00:18:42,320 Speaker 1: even richer way to think about this. And this is 286 00:18:42,359 --> 00:18:45,200 Speaker 1: something you hear me talk about on almost every episode. 287 00:18:45,240 --> 00:18:49,280 Speaker 1: This is the issue of the internal model. So in 288 00:18:49,320 --> 00:18:53,280 Speaker 1: the darkness of your skull, you have a model of 289 00:18:53,359 --> 00:18:55,560 Speaker 1: what the world is and how it's working, and this 290 00:18:55,600 --> 00:18:58,399 Speaker 1: is what gives you an understanding of what's going on 291 00:18:58,520 --> 00:19:01,960 Speaker 1: out there, and it gives you your pre So imagine 292 00:19:01,960 --> 00:19:05,879 Speaker 1: you hear a comedian tell his story. The comedian says, 293 00:19:06,320 --> 00:19:08,959 Speaker 1: so I walked into the doctor's office and the doctor 294 00:19:08,960 --> 00:19:11,159 Speaker 1: says to me, take off your clothes and put them 295 00:19:11,200 --> 00:19:14,919 Speaker 1: there in the corner. Next to mine. Now, what the 296 00:19:14,920 --> 00:19:18,800 Speaker 1: comedian's doing here is taking advantage of the assumptions of 297 00:19:18,880 --> 00:19:23,240 Speaker 1: your internal model, the thoughts that went unthunk, even though 298 00:19:23,240 --> 00:19:26,080 Speaker 1: they certainly could have been true that the doctor was naked, 299 00:19:26,320 --> 00:19:29,720 Speaker 1: but they were never even considered until you were told 300 00:19:29,760 --> 00:19:34,440 Speaker 1: that information, and then you have to retrospectively revise your 301 00:19:34,480 --> 00:19:37,399 Speaker 1: whole model of that situation. Or take the joke I 302 00:19:37,480 --> 00:19:40,600 Speaker 1: mentioned earlier about how my dog used to chase people 303 00:19:40,600 --> 00:19:44,240 Speaker 1: on bikes a lot. Linguistically, this could have been interpreted 304 00:19:44,280 --> 00:19:47,040 Speaker 1: by your brain as the dog riding the bike, and 305 00:19:47,119 --> 00:19:50,639 Speaker 1: possibly some neurons in your brain entertain that relationship for 306 00:19:50,720 --> 00:19:53,239 Speaker 1: a fraction of a second, but then they dismiss it, 307 00:19:53,600 --> 00:19:57,919 Speaker 1: and so that unconscious possibility never even gets close to 308 00:19:57,960 --> 00:20:01,200 Speaker 1: your consciousness until you suddenly have to do a wholesale 309 00:20:01,680 --> 00:20:05,320 Speaker 1: go back to the beginning and re understand the whole situation. 310 00:20:05,640 --> 00:20:08,960 Speaker 1: And by the way, while we're talking about subverting expectations, 311 00:20:09,000 --> 00:20:11,640 Speaker 1: this is not just used by comedians, but also by 312 00:20:12,119 --> 00:20:16,080 Speaker 1: mystery novelists and magicians. They all have something in common. 313 00:20:16,600 --> 00:20:22,320 Speaker 1: They rely on surprising your internal model to entertain. So 314 00:20:22,480 --> 00:20:25,800 Speaker 1: for the mystery novelists, it's the plot twist They set 315 00:20:26,080 --> 00:20:28,840 Speaker 1: everything up for you, and if they're doing their job right, 316 00:20:28,920 --> 00:20:32,560 Speaker 1: they know that all these clues can be scattered around you. 317 00:20:32,960 --> 00:20:35,600 Speaker 1: But right now you think a particular model of the 318 00:20:35,640 --> 00:20:39,440 Speaker 1: world is true, and then they surprise you by showing aha, 319 00:20:39,520 --> 00:20:43,040 Speaker 1: all these things you saw are consistent with a different 320 00:20:43,119 --> 00:20:47,040 Speaker 1: structure than the one you assumed, and with the magician, 321 00:20:47,119 --> 00:20:49,840 Speaker 1: it's the same thing. They move their hands, they show 322 00:20:49,880 --> 00:20:52,240 Speaker 1: you this, they draw your attention to that, and all 323 00:20:52,280 --> 00:20:56,080 Speaker 1: along they are making sure that you believe a particular 324 00:20:56,240 --> 00:20:59,399 Speaker 1: model of the world. They need you to believe that 325 00:20:59,480 --> 00:21:03,639 Speaker 1: everything is operating one way, and then they violate your expectation. 326 00:21:03,760 --> 00:21:08,280 Speaker 1: They flout your brain's predictions and leave you reveling in 327 00:21:08,320 --> 00:21:12,080 Speaker 1: the mystery that one thing seemed true, but you're now 328 00:21:12,080 --> 00:21:14,720 Speaker 1: looking at a different situation. And if you were that 329 00:21:15,160 --> 00:21:18,480 Speaker 1: space alien trying to figure out humans, you'd probably notice 330 00:21:18,480 --> 00:21:21,119 Speaker 1: that we spend a lot of our time flocking to 331 00:21:21,640 --> 00:21:26,760 Speaker 1: mystery novelists and magicians and comedians. You would fly back 332 00:21:26,800 --> 00:21:29,400 Speaker 1: to your planet and try to explain to your alien 333 00:21:29,480 --> 00:21:34,600 Speaker 1: colleagues that humans continuously pay money to have these professionals 334 00:21:34,840 --> 00:21:39,240 Speaker 1: give us some sort of story and then subvert our expectations. 335 00:21:39,480 --> 00:21:43,720 Speaker 1: So why do we find this appealing. One possibility is that, 336 00:21:44,080 --> 00:21:47,280 Speaker 1: as we're always trying to build a model of the world, 337 00:21:47,840 --> 00:21:52,479 Speaker 1: we derive pleasure from the discovery of a flaw in 338 00:21:52,560 --> 00:21:57,320 Speaker 1: our model. In other words, we are machines built to 339 00:21:57,440 --> 00:22:00,879 Speaker 1: self correct, and it is rewarding to find an error 340 00:22:00,920 --> 00:22:03,800 Speaker 1: and fix it. So part of the joy of humor 341 00:22:03,920 --> 00:22:06,960 Speaker 1: is the feeling that you had a model and now 342 00:22:07,000 --> 00:22:09,440 Speaker 1: you have a better one, a model that has more 343 00:22:09,840 --> 00:22:14,000 Speaker 1: explanatory power. So in the three guys walk into a 344 00:22:14,040 --> 00:22:17,000 Speaker 1: bar joke, the first guy sets an example, the second 345 00:22:17,040 --> 00:22:21,119 Speaker 1: guy gets your internal model to believe that it understands 346 00:22:21,119 --> 00:22:24,119 Speaker 1: a pattern, and then the third guy reveals there's a 347 00:22:24,600 --> 00:22:28,000 Speaker 1: different way, a broader way that you could have understood 348 00:22:28,240 --> 00:22:33,520 Speaker 1: the whole premise, I suggest we find it rewarding to 349 00:22:33,680 --> 00:22:36,960 Speaker 1: change the internal model, and this is what solving riddles 350 00:22:37,040 --> 00:22:41,120 Speaker 1: is about, or why people listen to science podcasts. There 351 00:22:41,200 --> 00:22:44,840 Speaker 1: is some pleasure derived from the realization that your model 352 00:22:45,000 --> 00:22:49,200 Speaker 1: was incomplete and now you see things with a broader 353 00:22:49,280 --> 00:22:51,280 Speaker 1: view than you were able to just a moment ago. 354 00:22:51,640 --> 00:22:54,840 Speaker 1: At its heart, I suggest that comedy is all about 355 00:22:54,920 --> 00:22:58,040 Speaker 1: thinking that you have the world understood and then finding 356 00:22:58,119 --> 00:23:01,560 Speaker 1: you didn't and you now have of a bigger model, 357 00:23:01,800 --> 00:23:05,480 Speaker 1: and again when the change is harmless, not threatening, then 358 00:23:05,680 --> 00:23:08,040 Speaker 1: we find it funny. Now, I want to take a 359 00:23:08,080 --> 00:23:10,520 Speaker 1: one minute tangent here to tackle a question that I've 360 00:23:10,560 --> 00:23:15,600 Speaker 1: been wondering about for a while. Can artificial intelligence be funny? 361 00:23:15,800 --> 00:23:18,120 Speaker 1: And the answer to this, I think is very illuminating. 362 00:23:18,760 --> 00:23:22,080 Speaker 1: On the one hand, AI can sometimes be hilarious and 363 00:23:22,119 --> 00:23:24,919 Speaker 1: tell you great jokes, but this is because it is 364 00:23:25,000 --> 00:23:28,800 Speaker 1: repeating or modifying a joke that has been said somewhere 365 00:23:28,920 --> 00:23:31,920 Speaker 1: in the vast corpus of human writing, even if you've 366 00:23:31,960 --> 00:23:34,639 Speaker 1: never heard it. A couple of episodes ago, I named 367 00:23:34,680 --> 00:23:38,680 Speaker 1: this the intelligence echo illusion, by which I simply mean 368 00:23:38,720 --> 00:23:42,000 Speaker 1: that we often mistake the echo of things that other 369 00:23:42,040 --> 00:23:47,040 Speaker 1: people have said before for intelligence in AI, or in 370 00:23:47,080 --> 00:23:50,480 Speaker 1: this case, for true comedy in AI. But it's nothing 371 00:23:50,520 --> 00:23:53,440 Speaker 1: but repeat in any case. Although AI can repeat a 372 00:23:53,480 --> 00:23:56,960 Speaker 1: good joke, what AI stinks at is making up an 373 00:23:57,200 --> 00:24:00,960 Speaker 1: entirely new joke. I did some experiment to drill down 374 00:24:00,960 --> 00:24:04,320 Speaker 1: on this. It's not because AI can't figure out what 375 00:24:04,359 --> 00:24:08,400 Speaker 1: people expect next and then shift away from that. Instead, 376 00:24:08,400 --> 00:24:11,360 Speaker 1: it's because a good joke has to replace the expectation 377 00:24:11,840 --> 00:24:15,520 Speaker 1: with an alternative that also makes sense with a new frame. 378 00:24:16,040 --> 00:24:20,240 Speaker 1: The punchline can't just be unexpected. Instead, it has to 379 00:24:20,280 --> 00:24:25,880 Speaker 1: be cleverly engineered to have some second meaning, a second interpretation. 380 00:24:26,520 --> 00:24:28,600 Speaker 1: So I'll give you an example that I just ran 381 00:24:28,640 --> 00:24:31,840 Speaker 1: this morning. I didn't want chat gpt to tell me 382 00:24:31,920 --> 00:24:33,960 Speaker 1: a joke i'd heard before, so I forced it to 383 00:24:34,000 --> 00:24:36,439 Speaker 1: make up something new by prompting it to tell me 384 00:24:36,480 --> 00:24:40,280 Speaker 1: a joke about lobsters and peanut butter. So here's what 385 00:24:40,280 --> 00:24:41,000 Speaker 1: it came up with. 386 00:24:41,280 --> 00:24:44,720 Speaker 2: Three lobsters walk into a grocery store. The first lobster 387 00:24:44,800 --> 00:24:47,520 Speaker 2: goes to the seafood section and asks for butter. The 388 00:24:47,560 --> 00:24:50,000 Speaker 2: grocer gives him a tub of butter, and he happily 389 00:24:50,040 --> 00:24:53,359 Speaker 2: scuttles away. The second lobster goes to the same section 390 00:24:53,480 --> 00:24:56,200 Speaker 2: and asks for butter. The grocer gives him a tub 391 00:24:56,240 --> 00:24:59,920 Speaker 2: of butter, and he too happily scuttles away. The third 392 00:25:00,480 --> 00:25:03,399 Speaker 2: goes to the grocery stores pantry section and asks for 393 00:25:03,480 --> 00:25:08,200 Speaker 2: peanut butter. The grocer looks surprised and asks why peanut butter. 394 00:25:08,600 --> 00:25:10,960 Speaker 2: Aren't you going to cook with butter like the other lobsters. 395 00:25:11,359 --> 00:25:15,199 Speaker 2: The third lobster replies, Nah, I'm allergic to butter, I 396 00:25:15,240 --> 00:25:17,160 Speaker 2: always shell out for peanut butter instead. 397 00:25:17,760 --> 00:25:20,920 Speaker 1: What now, I would call that the dumbest joke I've 398 00:25:20,920 --> 00:25:24,119 Speaker 1: ever heard, But it doesn't even qualify as a joke. 399 00:25:24,400 --> 00:25:28,959 Speaker 1: Why because the punchline, while it is a violation of expectation, 400 00:25:29,640 --> 00:25:34,160 Speaker 1: doesn't offer a second interpretation that makes sense. So crafting 401 00:25:34,200 --> 00:25:36,680 Speaker 1: a joke, at least for the moment, seems to be 402 00:25:36,680 --> 00:25:40,399 Speaker 1: beyond the scope of large language models. They have no 403 00:25:40,600 --> 00:25:45,439 Speaker 1: problem understanding that the structure of joke requires violating expectation, 404 00:25:45,840 --> 00:25:49,240 Speaker 1: but they have no idea how to violate it. They 405 00:25:49,240 --> 00:25:52,080 Speaker 1: don't know how to construct something that makes sense on 406 00:25:52,119 --> 00:25:55,199 Speaker 1: two levels at the same time, which appears to be 407 00:25:55,400 --> 00:25:58,959 Speaker 1: a requirement of humor. Now, let's return to the question 408 00:25:59,080 --> 00:26:02,000 Speaker 1: that the space al asked at the beginning. Maybe it 409 00:26:02,040 --> 00:26:06,840 Speaker 1: now understands why violations of expectation amuse humans as long 410 00:26:06,840 --> 00:26:10,640 Speaker 1: as those violations are harmless. But why do humans engage 411 00:26:10,720 --> 00:26:15,080 Speaker 1: in this very loud monkey call that they label laughter? 412 00:26:15,800 --> 00:26:18,680 Speaker 1: And this is a good question because the alien notices 413 00:26:18,800 --> 00:26:23,520 Speaker 1: that when you're having other emotions, you typically just experience 414 00:26:23,600 --> 00:26:28,199 Speaker 1: them internally. When you're feeling shy, you don't do a 415 00:26:28,240 --> 00:26:31,960 Speaker 1: high pitched yell when you're feeling morose. You don't sing 416 00:26:32,040 --> 00:26:35,400 Speaker 1: and clap when you eat something and you find it delicious. 417 00:26:35,480 --> 00:26:37,959 Speaker 1: You don't stand up in the restaurant and scream so 418 00:26:38,000 --> 00:26:41,440 Speaker 1: that all the other diners know it. You simply experience 419 00:26:41,560 --> 00:26:45,120 Speaker 1: emotions on the inside. So when we find something funny, 420 00:26:45,400 --> 00:26:50,880 Speaker 1: why does that physically trigger these high amplitude, low frequency vocalizations. 421 00:26:51,400 --> 00:26:54,760 Speaker 1: Why does your diaphragm contract over and over causing these 422 00:26:55,280 --> 00:26:59,080 Speaker 1: rapid exhalations which cause your vocal cords to rapidly open 423 00:26:59,119 --> 00:27:03,200 Speaker 1: and close create a loud sounds. Now, this is strange. 424 00:27:03,280 --> 00:27:06,960 Speaker 1: Right to appreciate this, ask yourself a different kind of question. 425 00:27:07,119 --> 00:27:10,800 Speaker 1: Why don't humans have the equivalent of a comedy club 426 00:27:11,200 --> 00:27:15,880 Speaker 1: in the domain of beautiful art. Imagine you sit down 427 00:27:15,920 --> 00:27:18,280 Speaker 1: at a museum with a lot of other people, and 428 00:27:18,320 --> 00:27:21,600 Speaker 1: the mc brings out a wonderful painting for everyone to 429 00:27:21,640 --> 00:27:25,360 Speaker 1: stare at, and then wheels out a beautiful statue, let's say, 430 00:27:25,400 --> 00:27:28,680 Speaker 1: carved by Michaelangelo, and so on. You can't really imagine 431 00:27:28,680 --> 00:27:32,159 Speaker 1: that you'd get a bunch of people physically making weird 432 00:27:32,240 --> 00:27:36,879 Speaker 1: rhythmic sounds and filling the hall with noise. Instead, people 433 00:27:36,920 --> 00:27:39,800 Speaker 1: go to museums and they quietly walk around and they're 434 00:27:39,840 --> 00:27:42,680 Speaker 1: filled with a sense of beauty. But it's a private, 435 00:27:43,040 --> 00:27:47,720 Speaker 1: quiet experience. So the question is why is laughter different? 436 00:27:48,520 --> 00:27:50,720 Speaker 1: So in trying to understand this, one can ask the 437 00:27:50,800 --> 00:27:56,600 Speaker 1: question of who else laughs? As in what other species? 438 00:27:56,920 --> 00:27:59,639 Speaker 1: When we think about humans in relation to other species, 439 00:27:59,680 --> 00:28:03,639 Speaker 1: we see that other species are collaborative and seem to 440 00:28:03,640 --> 00:28:07,760 Speaker 1: have emotions like pain and hunger. But are they laughing? 441 00:28:08,400 --> 00:28:12,040 Speaker 1: And the surprising answer is it appears some other animals 442 00:28:12,119 --> 00:28:14,080 Speaker 1: do laugh, or at least they do things that are 443 00:28:14,160 --> 00:28:19,200 Speaker 1: very similar to human laughter. For example, our primate friends, 444 00:28:19,320 --> 00:28:24,879 Speaker 1: the chimpanzees and bonobo's and gorillas and orangutans make these 445 00:28:24,960 --> 00:28:28,560 Speaker 1: vocalizations during play, and it seems to resemble the way 446 00:28:28,600 --> 00:28:32,600 Speaker 1: that humans laugh. These sounds tend to be softer and 447 00:28:32,680 --> 00:28:36,000 Speaker 1: more rhythmic compared to human laughter, but it appears to 448 00:28:36,080 --> 00:28:40,920 Speaker 1: serve a similar function in social interactions. So here is 449 00:28:40,920 --> 00:28:45,600 Speaker 1: an adolescent gorilla making these sounds when the zookeeper tickles 450 00:28:45,600 --> 00:29:00,320 Speaker 1: his foot through the bars. A link the video on 451 00:29:00,360 --> 00:29:03,280 Speaker 1: the show notes, and you can see the gorilla pulls 452 00:29:03,280 --> 00:29:05,800 Speaker 1: his foot away when it tickles, but then he presents 453 00:29:05,840 --> 00:29:09,520 Speaker 1: it again to be tickled. Another time, so you can 454 00:29:09,560 --> 00:29:13,400 Speaker 1: hear these sounds during physical play like tickling or chasing, 455 00:29:13,720 --> 00:29:17,520 Speaker 1: and the hypothesis is that it signals that the interaction 456 00:29:17,680 --> 00:29:22,480 Speaker 1: is playful rather than aggressive. Almost all animals play because 457 00:29:22,480 --> 00:29:24,880 Speaker 1: it helps them figure out how to get along with 458 00:29:24,960 --> 00:29:28,120 Speaker 1: others and how to build skills that they're gonna need later, 459 00:29:28,800 --> 00:29:32,320 Speaker 1: and so laughter is a broadcast signal to the others 460 00:29:32,360 --> 00:29:35,320 Speaker 1: to say, this is not actually serious. This is play. 461 00:29:35,360 --> 00:29:37,840 Speaker 1: In other words, I'm not actually trying to hurt you, 462 00:29:38,360 --> 00:29:40,760 Speaker 1: and even though we're being physical and wrestling or whatever, 463 00:29:40,840 --> 00:29:43,520 Speaker 1: I'm just trying to figure out what I will need 464 00:29:43,600 --> 00:29:46,200 Speaker 1: later in life. And it's not just primates. You can 465 00:29:46,240 --> 00:29:51,760 Speaker 1: also hear laughter in rats. They do this ultrasonic chirping 466 00:29:51,840 --> 00:29:54,320 Speaker 1: at fifty killer hurts. This is really high frequency, so 467 00:29:54,320 --> 00:29:56,120 Speaker 1: you can't hear this with your ears, but this can 468 00:29:56,160 --> 00:29:58,719 Speaker 1: be measured with a microphone and then transferred to our 469 00:29:58,840 --> 00:30:01,600 Speaker 1: range so we can hear it. And rat laughter sounds 470 00:30:01,640 --> 00:30:15,160 Speaker 1: like this, And it turns out that rats do this 471 00:30:15,200 --> 00:30:17,440 Speaker 1: when they play with each other and also when they 472 00:30:17,480 --> 00:30:20,760 Speaker 1: are being tickled by humans. This seems to be a 473 00:30:20,960 --> 00:30:25,160 Speaker 1: form of laughter, and it's associated with positive emotions and 474 00:30:25,240 --> 00:30:28,480 Speaker 1: social bonding and By the way, rats that chirp more 475 00:30:28,520 --> 00:30:32,240 Speaker 1: frequently tend to be more playful and sociable. And it's 476 00:30:32,280 --> 00:30:35,440 Speaker 1: not just rats, but dogs also. They do something called 477 00:30:35,680 --> 00:30:40,160 Speaker 1: play panting when they're doing social play, and some researchers 478 00:30:40,200 --> 00:30:44,440 Speaker 1: think that this is like laughter. The dogs pant with 479 00:30:44,520 --> 00:30:48,600 Speaker 1: this rhythmic, breathy sound, and they do this during playful interactions. 480 00:30:48,760 --> 00:30:50,600 Speaker 1: But it's not because they're out of breath. It's that 481 00:30:50,640 --> 00:30:54,200 Speaker 1: the signals to other dogs that their behavior is friendly 482 00:30:54,360 --> 00:30:57,320 Speaker 1: and non threatening. And you know where else you find 483 00:30:57,360 --> 00:31:01,960 Speaker 1: these physiologic signals that are like laughter dolphins. Dolphins do 484 00:31:02,000 --> 00:31:05,240 Speaker 1: all kinds of vocalizations like whistles and clicks, and these 485 00:31:05,280 --> 00:31:08,960 Speaker 1: seem to serve a similar function to laughter in terms 486 00:31:09,040 --> 00:31:13,560 Speaker 1: of reinforcing social bonds and communication about what is the 487 00:31:13,640 --> 00:31:16,600 Speaker 1: threat and what is not. So the latest estimate is 488 00:31:16,640 --> 00:31:20,560 Speaker 1: that there are at least sixty five animal species who 489 00:31:20,760 --> 00:31:24,560 Speaker 1: seem to laugh. And if you are the alien scientist, 490 00:31:24,680 --> 00:31:28,160 Speaker 1: this is a really important clue. Essentially, in all these 491 00:31:28,240 --> 00:31:32,240 Speaker 1: cases you detect the same general story that these laughter 492 00:31:32,520 --> 00:31:37,120 Speaker 1: like sounds are employed to indicate that the behaviors are playful, 493 00:31:37,160 --> 00:31:40,400 Speaker 1: they're not aggressive. In other words, I'm biting you, but 494 00:31:40,440 --> 00:31:43,800 Speaker 1: I'm not really trying to hurt you. And across species 495 00:31:43,800 --> 00:31:46,960 Speaker 1: you find that these laughter signals are used to strengthen 496 00:31:47,080 --> 00:32:06,720 Speaker 1: social bonds and bring the group closer together. Okay, but 497 00:32:06,800 --> 00:32:09,560 Speaker 1: the exact nature of laughter and animals may still be 498 00:32:09,600 --> 00:32:11,840 Speaker 1: a little bit different from humans because we have our 499 00:32:11,880 --> 00:32:16,160 Speaker 1: own evolutionary pathway. So why do we laugh while like 500 00:32:16,280 --> 00:32:19,480 Speaker 1: our animal brethren, we laugh to indicate play, to tell 501 00:32:19,480 --> 00:32:22,120 Speaker 1: the other this is not serious, and in humans this 502 00:32:22,160 --> 00:32:26,680 Speaker 1: grows more subtle. We have more nuanced situations. So in 503 00:32:26,760 --> 00:32:30,760 Speaker 1: human societies, if someone makes a social mistake, or someone 504 00:32:30,840 --> 00:32:36,320 Speaker 1: finds themselves uncomfortable or risks someone else's standing, laughter is 505 00:32:36,360 --> 00:32:40,560 Speaker 1: a broadcast signal to say, this is play, don't worry 506 00:32:40,640 --> 00:32:43,640 Speaker 1: about it. And there's another suggestion too, made by my 507 00:32:43,720 --> 00:32:47,160 Speaker 1: colleague Vs. Rahma Chandren in ninety eight, and he suggested 508 00:32:47,200 --> 00:32:50,200 Speaker 1: that laughter is a way of alerting those around you 509 00:32:50,880 --> 00:32:54,640 Speaker 1: that there's something dangerous, but it's no longer a threat. Essentially, 510 00:32:54,920 --> 00:32:58,400 Speaker 1: laughter is like a monkey call that tells everyone else 511 00:32:58,920 --> 00:33:02,080 Speaker 1: things are fine. It carries information that there has been 512 00:33:02,120 --> 00:33:06,480 Speaker 1: a false alarm. So you see the man's ladder fall 513 00:33:06,560 --> 00:33:10,200 Speaker 1: backwards and he lands on a haystack, and everyone needs 514 00:33:10,240 --> 00:33:12,920 Speaker 1: to be alerted that he's okay, So you send out 515 00:33:12,920 --> 00:33:17,120 Speaker 1: this call. If he hit rocks, nobody would laugh. On 516 00:33:17,160 --> 00:33:18,960 Speaker 1: this note, I'll just mention I have a sort of 517 00:33:19,040 --> 00:33:21,800 Speaker 1: painful memory from when I was ten years old and 518 00:33:21,840 --> 00:33:24,120 Speaker 1: I was in a martial arts class and the instructor 519 00:33:24,400 --> 00:33:27,240 Speaker 1: picked up a dumbbell with several plates on it, and 520 00:33:27,320 --> 00:33:29,840 Speaker 1: he didn't realize that there wasn't a cuff on the end, 521 00:33:30,160 --> 00:33:33,400 Speaker 1: and all the plates slipped off and almost landed on 522 00:33:33,440 --> 00:33:36,520 Speaker 1: his foot but missed, and I laughed, and I got 523 00:33:36,520 --> 00:33:39,520 Speaker 1: in trouble for it, and everyone thought it was deeply inappropriate. 524 00:33:39,960 --> 00:33:42,520 Speaker 1: And the important part is that I felt terrible because 525 00:33:42,520 --> 00:33:44,600 Speaker 1: I didn't find it funny. So I had no idea 526 00:33:44,640 --> 00:33:47,160 Speaker 1: why that had come out of my mouth. But later 527 00:33:47,600 --> 00:33:50,720 Speaker 1: I came to understand that laughter is an alerting system, 528 00:33:51,160 --> 00:33:53,520 Speaker 1: and that gave me some insight into what had happened. 529 00:33:53,560 --> 00:33:57,040 Speaker 1: I saw the plates slipping off, and I felt terrified, 530 00:33:57,360 --> 00:33:59,240 Speaker 1: and then I saw that they all missed his foot 531 00:33:59,240 --> 00:34:01,960 Speaker 1: by a few inches, and I was alerting the rest 532 00:34:01,960 --> 00:34:05,000 Speaker 1: of the tribe that things were okay. I didn't expect 533 00:34:05,200 --> 00:34:08,680 Speaker 1: people to laugh with me. I was simply communicating that 534 00:34:08,719 --> 00:34:11,080 Speaker 1: things were not scary like we all thought for just 535 00:34:11,120 --> 00:34:13,920 Speaker 1: a moment that they were about to be. Now, there 536 00:34:13,960 --> 00:34:16,759 Speaker 1: are physical benefits to laughter. This may be true in 537 00:34:16,840 --> 00:34:19,760 Speaker 1: animals too, but we really get this as humans. Laughter 538 00:34:19,920 --> 00:34:23,680 Speaker 1: triggers the release of endorphins, which are natural painkillers and 539 00:34:23,719 --> 00:34:28,880 Speaker 1: mood enhancers. So laughter reduces the perception of pain, improves 540 00:34:28,920 --> 00:34:32,120 Speaker 1: overall pain tolerance, and it can improve mood. And it 541 00:34:32,160 --> 00:34:36,680 Speaker 1: also improves immune function by increasing the production of antibodies 542 00:34:36,680 --> 00:34:40,239 Speaker 1: and activating immune cells. And generally people find that it 543 00:34:40,320 --> 00:34:44,880 Speaker 1: reduces the level of stress hormones like cortisol and adrenaline. 544 00:34:45,040 --> 00:34:46,960 Speaker 1: So there are all kinds of cool things that laughter 545 00:34:47,040 --> 00:34:49,000 Speaker 1: can do. But what I want to return to is 546 00:34:49,080 --> 00:34:51,680 Speaker 1: the social aspect of it. And one of the things 547 00:34:51,680 --> 00:34:55,400 Speaker 1: that's hard to miss is how laughter can be contagious. 548 00:34:55,840 --> 00:34:58,319 Speaker 1: For example, go to YouTube to find a video of 549 00:34:58,800 --> 00:35:02,880 Speaker 1: parrots laughing. They're just impersonating their human owners, but it 550 00:35:02,960 --> 00:35:06,920 Speaker 1: is impossible to watch those videos and not laugh yourself. 551 00:35:07,160 --> 00:35:09,719 Speaker 1: As I mentioned before, there are other weird cases where 552 00:35:09,719 --> 00:35:12,239 Speaker 1: people laugh when they shouldn't, like when they hear some 553 00:35:12,400 --> 00:35:16,400 Speaker 1: terrible news, because they just have too much emotion. Weirdly, 554 00:35:17,000 --> 00:35:21,040 Speaker 1: this often has the property of becoming contagious. So someone 555 00:35:21,080 --> 00:35:24,000 Speaker 1: hears something terrible and can't stop laughing, not because they 556 00:35:24,040 --> 00:35:26,360 Speaker 1: believe it's funny, but because they have so much emotion 557 00:35:26,440 --> 00:35:29,279 Speaker 1: that needs release. And what often happens is that the 558 00:35:29,360 --> 00:35:32,719 Speaker 1: other people are horrified at first, but then they start 559 00:35:32,800 --> 00:35:35,640 Speaker 1: laughing too, because it's very hard to help it. In fact, 560 00:35:35,680 --> 00:35:39,959 Speaker 1: something I find fascinating is an expression that comedians say 561 00:35:40,040 --> 00:35:43,000 Speaker 1: in private, which is that a comedian's two best friends 562 00:35:43,440 --> 00:35:48,080 Speaker 1: are alcohol and density. Now the alcohol is obvious, but 563 00:35:48,160 --> 00:35:52,200 Speaker 1: the density is worth unpacking. Comedians have always noted that 564 00:35:52,320 --> 00:35:54,040 Speaker 1: if they get up to perform in front of a 565 00:35:54,040 --> 00:35:57,200 Speaker 1: crowd of people who are spread out around the club, 566 00:35:57,800 --> 00:36:00,560 Speaker 1: the exact same jokes aren't gonna go so well. They're 567 00:36:00,560 --> 00:36:03,640 Speaker 1: not going to trigger the same laughter as they would 568 00:36:03,680 --> 00:36:07,320 Speaker 1: if everyone was bunched up closely together. Why Because laughter 569 00:36:07,440 --> 00:36:11,680 Speaker 1: spreads contagiously as long as everyone is sitting tightly packed. 570 00:36:11,680 --> 00:36:15,120 Speaker 1: It's essentially impossible for someone to sit in the middle 571 00:36:15,120 --> 00:36:18,840 Speaker 1: of a laughing crowd and not laugh themselves. Now again, 572 00:36:19,160 --> 00:36:23,520 Speaker 1: evolutionary theorists argue that contagious laughter is a mechanism to 573 00:36:24,000 --> 00:36:27,080 Speaker 1: foster a sense of unity in a group and that 574 00:36:27,200 --> 00:36:31,240 Speaker 1: could help group survival. I'm not sure about the strength 575 00:36:31,280 --> 00:36:33,200 Speaker 1: of that argument, because there are lots of ways that 576 00:36:33,239 --> 00:36:36,759 Speaker 1: groups bond. Just look at something like fighting together. Look 577 00:36:36,760 --> 00:36:40,800 Speaker 1: at the Spartans. They were tightly knit because they fought 578 00:36:40,840 --> 00:36:44,360 Speaker 1: side by side and defended each other's lives. But I 579 00:36:44,440 --> 00:36:46,680 Speaker 1: was thinking about this last night and it struck me 580 00:36:46,719 --> 00:36:49,400 Speaker 1: that we don't really know if the Spartans were funny 581 00:36:49,520 --> 00:36:52,880 Speaker 1: or not because they were such famous fighters. Maybe they 582 00:36:52,880 --> 00:36:55,160 Speaker 1: were hilarious when they were sitting around the camp and 583 00:36:55,200 --> 00:36:58,160 Speaker 1: eating dinner, and that's what caused the bonding. We just 584 00:36:58,200 --> 00:37:01,560 Speaker 1: don't know. But the general are argument is that contagious 585 00:37:01,600 --> 00:37:05,279 Speaker 1: laughter strengthens group cohesion. And by the way, there are 586 00:37:05,320 --> 00:37:09,200 Speaker 1: other social aspects to laughter beyond contagion. One thing I 587 00:37:09,280 --> 00:37:13,839 Speaker 1: find fascinating is laughter within hierarchies, where the person at 588 00:37:13,840 --> 00:37:17,759 Speaker 1: the top laughs the loudest. The king and the plebeians 589 00:37:17,840 --> 00:37:20,000 Speaker 1: don't laugh in the same way. You can see this 590 00:37:20,160 --> 00:37:25,759 Speaker 1: clearly in very hierarchically structured cultures where laughter is used 591 00:37:25,760 --> 00:37:29,760 Speaker 1: as a way to show deference or respect to authority figures, 592 00:37:30,000 --> 00:37:33,719 Speaker 1: for example, laughing softly when superior makes a joke, even 593 00:37:33,760 --> 00:37:37,520 Speaker 1: if it's not particularly funny as a way to show agreement. 594 00:37:37,760 --> 00:37:39,839 Speaker 1: And this is actually a good segue because I've told 595 00:37:39,840 --> 00:37:42,480 Speaker 1: you that when we look across the animal kingdom, we 596 00:37:42,560 --> 00:37:47,320 Speaker 1: see there are several plausible evolutionary stories for thinking about laughter. 597 00:37:47,840 --> 00:37:50,719 Speaker 1: But it's also worth noting that within the human species, 598 00:37:50,760 --> 00:37:54,600 Speaker 1: there are several cultural variations the way that laughter is 599 00:37:54,640 --> 00:37:58,680 Speaker 1: expressed and interpreted and used. It's not the same everywhere. 600 00:37:59,080 --> 00:38:04,040 Speaker 1: For example, in Western cultures, laughter is generally associated with 601 00:38:04,280 --> 00:38:08,200 Speaker 1: humor and used to express enjoyment or amusement or sarcasm. 602 00:38:08,640 --> 00:38:12,040 Speaker 1: But in East Asian cultures, laughter is not only a 603 00:38:12,080 --> 00:38:16,480 Speaker 1: response to humor but also a tool for managing social harmony. 604 00:38:16,840 --> 00:38:20,360 Speaker 1: For example, in Japan, people might laugh softly or politely, 605 00:38:20,760 --> 00:38:24,319 Speaker 1: even in awkward or uncomfortable situations, as a way to 606 00:38:24,400 --> 00:38:29,440 Speaker 1: diffuse tension or to avoid conflict. And in Mediterranean cultures 607 00:38:29,480 --> 00:38:32,520 Speaker 1: like in Italy and Greece, laughter tends to be more 608 00:38:32,560 --> 00:38:36,920 Speaker 1: exuberant and loud, and it often accompanies animated conversations and 609 00:38:37,040 --> 00:38:41,279 Speaker 1: it's seen as a sign of enthusiasm and engagement, Whereas 610 00:38:41,320 --> 00:38:45,520 Speaker 1: in Scandinavian cultures like Sweden and Norway, laughter tends to 611 00:38:45,560 --> 00:38:49,840 Speaker 1: be more subdued and controlled and loud laughter can be 612 00:38:49,880 --> 00:38:53,920 Speaker 1: perceived as inappropriate, and there are gender differences. In some 613 00:38:54,000 --> 00:38:57,880 Speaker 1: Middle Eastern cultures, men and women are expected to laugh differently. 614 00:38:57,920 --> 00:39:01,200 Speaker 1: Women are typically expected to laugh more softly or modestly 615 00:39:01,200 --> 00:39:04,200 Speaker 1: in public, whereas men are free to laugh loudly. In 616 00:39:04,239 --> 00:39:07,959 Speaker 1: Western societies, while there are no strict rules, studies show 617 00:39:08,000 --> 00:39:11,560 Speaker 1: that women tend to laugh more frequently than men at 618 00:39:11,600 --> 00:39:15,719 Speaker 1: social settings, often as a way of facilitating social interaction, 619 00:39:16,120 --> 00:39:18,560 Speaker 1: and by the way, the responses to laughter can also 620 00:39:18,640 --> 00:39:22,120 Speaker 1: be different. Just as an example, in Eastern European cultures 621 00:39:22,160 --> 00:39:27,080 Speaker 1: like Russia, laughter informal or serious contexts is viewed as 622 00:39:27,200 --> 00:39:31,000 Speaker 1: inappropriate and with suspicion, and what's done instead of laughter 623 00:39:31,120 --> 00:39:35,200 Speaker 1: is a quick or reserved smile, especially in professional settings. 624 00:39:35,640 --> 00:39:39,360 Speaker 1: But contrast this with Latin American cultures, where laughter is 625 00:39:39,400 --> 00:39:43,279 Speaker 1: generally more freely expressed and is a key part of 626 00:39:43,320 --> 00:39:47,839 Speaker 1: social interactions. People laugh easily in everyday conversations and they 627 00:39:47,920 --> 00:39:51,200 Speaker 1: use it as a way to express warmth and friendliness. 628 00:39:51,800 --> 00:39:55,959 Speaker 1: So laughter is a common human experience, but it does 629 00:39:56,000 --> 00:40:00,279 Speaker 1: get molded a bit by cultural norms and values. Let's 630 00:40:00,280 --> 00:40:03,160 Speaker 1: wrap up today's podcast. If you are the space Alien 631 00:40:03,200 --> 00:40:04,960 Speaker 1: and you have to go home to explain to your 632 00:40:05,000 --> 00:40:08,840 Speaker 1: colleagues what human laughter is about. You're going to find 633 00:40:09,200 --> 00:40:12,760 Speaker 1: there's not just one answer why, because there are many 634 00:40:12,800 --> 00:40:17,840 Speaker 1: different flavors of humor, from laughing at someone to laughing 635 00:40:17,920 --> 00:40:21,600 Speaker 1: with someone, to laughing at clever wordplay with two meanings. 636 00:40:22,000 --> 00:40:24,720 Speaker 1: And there's the kind of laughter where you are appreciating 637 00:40:25,040 --> 00:40:29,680 Speaker 1: masterful violation of expectation. And physically, there are different kinds 638 00:40:29,760 --> 00:40:33,000 Speaker 1: of laughter. Some humans have a quick contraction of the 639 00:40:33,000 --> 00:40:35,799 Speaker 1: diaphragm and they make a snort, or you might find 640 00:40:35,840 --> 00:40:39,200 Speaker 1: the unrestrained burst of laughter that we call a guffaw 641 00:40:39,960 --> 00:40:43,040 Speaker 1: fully engaging the respiratory muscles. Or you might hear the 642 00:40:43,440 --> 00:40:47,240 Speaker 1: puckish glee of a cackle, which is sharp and high pitched, 643 00:40:47,520 --> 00:40:51,359 Speaker 1: with rapid, irregular exhalations from the lungs. Or you might 644 00:40:51,440 --> 00:40:55,440 Speaker 1: spot the contentment of a chuckle, which is low pitched 645 00:40:55,480 --> 00:40:59,200 Speaker 1: and sustained, involving rhythmic contractions of the diaphragm and the 646 00:40:59,360 --> 00:41:04,320 Speaker 1: soft vocalizations. Or you might catch the slyness of a snicker, 647 00:41:04,480 --> 00:41:07,680 Speaker 1: or the innocence of a high pitched giggle, or the 648 00:41:07,680 --> 00:41:11,840 Speaker 1: thunderous roll of a belly laugh that deep, full bodied 649 00:41:11,840 --> 00:41:16,360 Speaker 1: contraction of the abdominal muscles. So if you're the space alien, 650 00:41:16,800 --> 00:41:19,560 Speaker 1: you'd have to conclude that humans seem to laugh for 651 00:41:19,600 --> 00:41:23,279 Speaker 1: a variety of reasons in a variety of ways, and 652 00:41:23,320 --> 00:41:27,200 Speaker 1: it's not as low bandwidth as you thought. In different circumstances, 653 00:41:27,440 --> 00:41:31,319 Speaker 1: it can signal play, it can strengthen social bonds, it 654 00:41:31,360 --> 00:41:35,640 Speaker 1: can reduce tensions, it can give emotional release, and it 655 00:41:35,680 --> 00:41:41,239 Speaker 1: can communicate. It can nonverbally broadcast amusement or agreement or 656 00:41:41,280 --> 00:41:45,279 Speaker 1: discomfort or false alarms. So while the alien and its 657 00:41:45,320 --> 00:41:49,439 Speaker 1: compatriots might be confused, we don't care because we love 658 00:41:49,560 --> 00:41:53,279 Speaker 1: to laugh. We have millions of years and billions of 659 00:41:53,320 --> 00:41:58,479 Speaker 1: neurons behind it, all pushing us towards mirth. Until next time, 660 00:41:58,960 --> 00:42:06,440 Speaker 1: may your neural path ways continue to be tickled. Go 661 00:42:06,480 --> 00:42:09,400 Speaker 1: to Eagleman dot com slash podcast for more information and 662 00:42:09,440 --> 00:42:13,040 Speaker 1: to find lots of reading about the science of humor. 663 00:42:13,440 --> 00:42:16,319 Speaker 1: Send me an email at podcast at eagleman dot com 664 00:42:16,320 --> 00:42:19,640 Speaker 1: with questions or discussion and check out. Subscribe to Inner 665 00:42:19,719 --> 00:42:22,880 Speaker 1: Cosmos on YouTube for videos of each episode and to 666 00:42:22,960 --> 00:42:26,200 Speaker 1: leave comments. Until next time. I'm David Eagleman, and this 667 00:42:26,400 --> 00:42:36,759 Speaker 1: is Inner Cosmos.